Chatter-proof vacuum controller unit



Nov. 26, 1963 A. E. BROUGHTON CHATTER-PROOF VACUUM CONTROLLER UNIT F/a Z w. m w W F d m N n m 4 W 5 m 4 ,2, J /J z 6 fi w .i

United States Patent 3,111,957 CHATTER-PROOF VACUUM CONTROLLER UNIT Arthur E. Broughton, Glens Falls, N.Y., assiguor to Frances J. Broughtou, Glens Falls, N.Y., and Douglas H. Newcomb, Hudson Falls, N.Y., as trustees Filed Feb.28, 1957, Ser. No. 643,187 2 Claims. (Cl. 137116.3)

This invention relates to vacuum cont-rollers, particularly adapted for use with paper making machinery and more particularly relates to a controller having an independent air relief valve communicating directly with the source of suction supply.

While the vacuum controller disclosed in my US. Patent Number 2,745,322, granted May 15, 1956, has worked relative-1y successfully and has materially reduced the chatter from my prior controllers while materially increasing the sensitivity and accuracy of control over my prior controllers, I have found that the rapid fluctuations produced in the control chamber towhich the diaphragm is responsive, still cause considerable chatter of the vaouum supply valve.

It is therefore an object of. my present invention to provide a vacuum controller which is particularly constructed to eliminate chatter of the suction control valve.

More specifically, it. is an object to provide a vacuum controller having a sealed control chamber communicating only with the source of suction supplied to the suction head.

Still more specifically, it is an object to provide a vacuum controller having a control chamber provided with a restricted communication passage affording communication with the source of suction supplied to the suction head, said controller including an air relief valve which communicates directly with the source of suction supplied to the suction head.

It is still a further object to provide a vacuum controller particularly designed to eliminate sudden pressure fluctuations within the control chamber.

These and other objects and advantages of my invention will more fully appear from the following description, made in connection with the accompanying drawings, wherein like reference characters refer to the same or similar parts throughout the several views, and in which:

FIG. 1 is a vertical sectional view showing my new controller; and

FIG. 2 is a horizontal sectional view taken substantially along the line 22 of FIG. 1; and

FIG. 3 is a side elevational view showing a suction system for paper making machines with my new controller incorporated therein.

As illustrated in FIG. 3, I provide a controller designated as an entirety by the letter A attached to a suction head such as the flat box as by an air leg 11, T-member 12 and withdrawal conduit 13, A drop leg 14 is connected with the vertical portion of T-member 12 and is sealed at its bottom by being submerged in the liquid confined in a reservoir tank 15. Any suitable source of suction supply may be provided such as a suction pump, not shown, and a suction conduit 16 communicates with the air leg 11 through a conduit 17 through which the flow of air is controlled by the vacuum controller A. The vacuum controller or control assembly designated by the letter A includes a vacuum control valve 18, an air relief valve 19 and a valve actuating mechanism including a diaphragm 20 mounted in a casing or casting designated by the numeral 21.

The lower portion of the casing 21 defines a valve control chamber 22 which is terminated at its upper end by the diaphragm 20. The lower end of the casing 21 3,1 1 1,957 Patented Nov. 26, 1963 ice has a restricted opening 21a which affords communication with the air leg 11 through a sensing tube designated by the numeral 21b. The purpose of the restricted orifice 21a is to retard the rate at which the pressures within the chamber 22 will vary. A spring 23 normally urges the diaphragm 29 upwardly with an adjustable predetermined force. An adjustable lower spring seat 24 having the screw threaded stem 25 permits the force to be varied in accordance with the required vacuum. An upper spring seat 26 is securely fixed to the center portion of the diaphragm 2t and forms a mounting for the actuating rod 27 which opens the air relief valve 19 against the force of a spring 28. The suction control valve 18 is actuated by a hollow tubular member 29 which is responsive to upward movement of the diaphragm for opening the valve 13 against the force of spring 28. Oh-

- viously, whenever the force exerted by the spring 23 exceeds the pull exerted by the vacuum in chamber 22, the suction control valve 18 will be opened by the upward shifting movement of the diaphragm 20 produced by the spring 23.

The rod 27 is securely anchored in fixed relation at its lower end to the diaphragm as by being fixed to the upper spring seat member 26. This connection may form an air tight seal to prevent communication between the chamber 22 and the atmosphere above the diaphragm 20 The upper portion of the rod 2'7 is slidably mounted in a guiding passage formed in a casting member 40 which is also formed to provide a double valve seat arrangement for the balanced lair relief valve 19. A v-alve element 19a slidably receives the rod 27 therethrou-gh and has a pair of beveled sealing surfaces normally held in seated position against the valve seats of the casting 46 as by a spring 28. When the suction in the chamber 22 exceeds the force exerted by the spring 23, the diaphragm 20 will pull down on the rod 27 and a suitable stop element 27a fixed to the rod 27 will retract the valve member 19a downwardly to open the same against the force of the spring 28, and thus permit positive air under positive atmospheric pressure to flow into the air leg 11 and thus reduce the suction in the flat box 10. When the suction is reduced in the air leg 11, the suction in the control chamber 22 is also relieved through the sensing tube 21b and restricted opening 21a. However, this will be relieved gradually, due to the restricted orifice 21a and also due to the fact that the how of air under positive atmospheric pressure communicates with the chamber 22 only through the suction air leg 11 in which suction is always maintained so that the movement of the diaphragm upwardly will be gradual and chattering of the valve 19 will thus be eliminated.

When the force exerted by the spring 23 exceeds the force exerted by the suction in chamber 22, the balanced vacuum control valve 18 will, of course, be opened to impose the vacuum in suction conduit 15 on the air leg 11. Whenever the valve 18 is open, the air relief valve 19 is, of course, closed. The vacuum control valve 18 is actuated by the hollow tubular member 29 which slidably receives the actuating rod 27 for the air relief valve. The upper end of the tubular member 29 is fixed to the suction control valve element 18a and the lower end of said tubular member 29 has a sleeve member 30 fixed thereto as by being threadably connected therewith, and said sleeve member is slidably mounted through the diaphragm 29 to permit said diaphragm to flex downwardly for actuating the air relief valve 19 as described, but said sleeve has a shoulder 30a formed around an intermediate portion thereof and said shoulder has a suitable sealing and cushioning member 31 which engages an annular guiding and reinforcing ring 32 mounted in fixed relation to the diaphragm 26' and surrounding the lower portion of said sleeve 30 in slidable relation thereto, but engaging the cushioned shoulder 39a to open the suction control valve 18 when the upwardly directed force of spring 23 exceeds the downward pull of the suction 22 on the diaphragm 20.

A casting 41 provides a pair of suitable beveled valve seats for the balanced suction control valve element 18a and the lower portion thereof slidably receives the tubular member 29 and any suitable means for providing a seal therebetween may be provided, such as the O-ring 42. An intermediate casting 43 is provided with a flange tor clamping the top of the diaphragm 20 to the bottom casting 21 and is securely fixed to the lower portion of the casting 41 by any suitable means. A gauge 44 may be provided to indicate the suction in the air leg 11 and flat box 10, and a manually operated valve 16a is provided in the main suction conduit 16.

Obviously, a number of flat boxes may be provided in underlying relation to the pulp carrying screen or wire 45 of the paper making machine, and each flat box is individually controlled by a separate controller assembly A to permit varying degrees of suction to be maintained on the layer of pulp supported by the wire 45.

It will be seen that I have provided a greatly improved vacuum controller specifically designed to entirely eliminate chatter of the two valves 18 and 19. This is done by connecting the control chamber 22 to the valve controlling positive air supply, only through the suction air leg 11 which by itself materially reduces the chatter, but also the restriction of the fiow of air into and out of said chamber by the restricted orifice 21a to retard the rate of fluctuation of suction in the control chamber 22. The rate of pressure change within the chamber is materially reduced thus reducing the rate at which the diaphragm will be oscillated by the changes in the suction in the flat box 10. It is apparent that said control chamber 22 is sealed from the atmosphere except for the restricted opening 21a pair of axially aligned .valves, a pair of concentrically arranged valve actuating elements operatively associated at one end with said pressure responsive actuating element and respectively connected at their other ends to said valve elements to selectively open and close said valve elements in response to variations in the pressure in said chamber. 2. The structure set forth in claim 1 and yieldable resilient means interposed between said two axially aligned valves to respectively urge the same apart, and valve seats for said valves being positioned to receive the respective valve elements when urged apart by said resilient means.

References Cited in the file of this patent UNITED STATES PATENTS 370,715 Smith Sept. 27, 1887 962,516 Mueller June 28, 1910 1,040,973 Barion Oct. 8, 1912 2,582,612 Williams Jan. 15, 1952 2,587,375 Paulsen Feb. 26, 1952 2,684,838 Rush July 27, 1954 2,707,966 Taplin May 10, 1955 2,731,026 Hughes Jan. 17, 1956 2,745,322 Broughton May 15, 1956 2,747,599 Watson May 29, 1956 2,950,730 Svensson Aug. 30, 1960 

1. A VACUUM CONTROLLER AND VALVE ASSEMBLY ACTUATED THEREBY COMPRISING A CONTROL CHAMBER, AN ACTUATING MEMBER COMMUNICATING WITH SAID CHAMBER AND RESPONSIVE FOR ACTUATION TO VARIATTIONS IN THE PRESSURE IN THE CHAMBER, A PAIR OF AXIALLY ALIGNED VALVES, A PAIR OF CONCENTRICALLY ARRANGED VALVE ACTUATING ELEMENTS OPERATIVELY ASSOCIATED AT ONE END WITH SAID PRESSURE RESPONSIVE ACTUATING ELEMENT AND RESPECTIVELY CONNECTED AT THEIR OTHER ENDS TO SAID VALVE ELEMENTS TO SELECTIVELY OPEN AND CLOSE SAID VALVE ELEMENTS IN RESPONSE TO VARIATIONS IN THE PRESSURE IN SAID CHAMBER. 